President James Polk, prior to the beginning of the Mexican-American War, had an idea for how to gain new territory for America. He was not going to limit the acquisitions solely to what could be gained with Mexico through military conflict south of Texas. He had his eyes on California and New Mexico, and he had a plan for how to get those two territories.
President James Polk, at the outbreak of the Mexican-American War, was concerned about the ramifications of a significant, drawn-out conflict. He was aware that a Whig military hero could emerge, just as William Henry Harrison had. See Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 750.
Following President James Polk’s announcement of war with Mexico, and Congress’ declaration of war, those in the Whig Party and those around the country had significantly different views of the war.
On the evening of April 24, 1846, Captain Seth Thornton and 68 American dragoons “went to confirm intelligence that a Mexican military force had crossed the Rio Grande” just miles away from where Brigadier General Zachary Taylor was camped. Daniel Walker Howe, What Hath God Wrought: Transformation of America, 1815-1848, 731.